In most houses and many similar structures, the floors are conventionally constructed by installing a series of narrow floor joists to provide support, and then placing sheets of plywood or the like on top of these to form the flooring surface. The sheets of plywood are nailed to the joists, and then carpet, linoleum, or other floor covering is typically installed on top of the plywood.
Due to the increasing expense and difficulty of obtaining fully seasoned wood products, there has been an increasing tendency to install joists which are not as fully seasoned, nor perhaps as true, as the builder might otherwise like. Unfortunately, once the wood fully dries, its curvature often changes, and the resulting irregularities and misalignment of the edges of the joists with the overlying plywood frequently results in numerous floor squeaks in the finished building. These squeaks often occur due to the plywood rubbing up and down against the shaft of a nail, where there is a gap between the top of the joist and the plywood which permits the plywood to flex up and down as a person or other object moves across the floor. Because it is usually necessary to remove a ceiling and/or carpeting or other floor covering to get at the source of the problem, repairs to correct such squeaks are typically very expensive.
The conventional measure which has been adopted in the construction industry in an attempt to overcome the problem of floor squeaks is to glue the plywood sheets to the joists using a conventional wood glue or the like. This technique has been marked by very modest success. Very commonly, once the wood has dried out, the resulting irregularities and misalignments become so great that the dried glue simply cracks or breaks and so does nothing to prevent the squeaks from developing. Also, because such glues set up within a limited period of time after they have been dispensed from their containers, the builder is obliged to place the plywood on the floor joists almost immediately after the glue has been laid thereon, which interferes with the builder's flexibility in managing the project; furthermore, in very hot or very cold climates, the glue tends to set up excessively fast, which aggravates this problem. Also, most such glues cannot be used when it is raining. Still further, once the glue has been placed on the floor joists, the construction crew can no longer walk about on the tops of the joists, which makes it very difficult to position and install the sheets of plywood, and when the crew slides the sheets of plywood along the tops of the joists into place, the edges of the sheets often scrape the glue off of the joists so that there is virtually none left to bond to the plywood.
An additional problem which is encountered when using the conventional construction methods described above is a lack of sound insulation between vertically adjoining rooms, as in an apartment complex. Impact noises, such as those of a person walking or dropping an object on the floor, are readily transmitted directly through the floor joists to the ceiling of the room below. While systems have been proposed for sound insulation of such floors, these have normally been prohibitively difficult and expensive to construct, particularly for use in low-cost construction projects such as public housing apartments, motels, and the like. And, of course, the conventional glueing technique described in the preceding paragraph does nothing to prevent the transmission of impact noises through the floor joists.
Accordingly, there exists a need for a method of constructing the floors of houses and like structures which eliminates squeaks, and which compensates for irregularities and misalignments which occur when the wooden floor joists dry out. Furthermore, there is a need for such a method which can be readily practiced in a variety of weather conditions, and which eases the task of moving about on the floor joists to align and install the sheets of plywood flooring. Still further, there exists a need for such a method which helps reduce the transmission of impact sounds in a vertical direction between adjoining rooms in a structure.